Chairman of the National Crime Prevention Council (NCPC), Mr Tan Kian Hoon, said: "Scammers are always devising new ways to cheat victims and the latest scam is a variant of the credit-for-sex scam.

"In this version, the ladies are portrayed to be from the Philippines and victims are asked to buy credits from a new platform, Money Online, or remit money to Philippines via Western Union and Moneygram."

A police spokesman said the authorities are concerned because this new trend not only involves new syndicates using similar tactics as those responsible for credit-for-sex scams, but also shows that there are different syndicates in diverse regions looking for victims here.

He said the new scam differed from those involving victims making advance payments to fraudsters for the purchase of goods, such as IT gadgets, phones or bicycles that are advertised on online portals.

Police said commercial crimes increased by 1,387 cases in the first six months of this year compared with the same period in 2014.

Within this category, cases like cheating involving e-commerce and credit-for-sex scams had a large increase.

Crimes involving e-commerce have risen sharply over the past three years - from 238 reported cases in 2012 to 510 cases in 2013, and 1,659 cases last year.

Credit-for-sex scam cases jumped from five between July and September last year to 285 for the same period this year.

It gets worse.

Between July and December last year, there were 66 credit-for-sex scam cases. In the first six months of this year, there were 640.

For e-commerce scams, numbers jumped from 613 cases in the first half of 2014, to 1,015 cases in the same period this year.

The total amount of money cheated was about $3.79 million.

It has become so bad that the Norton Cybersecurity Insights Report released on Nov 24 this year found 80 per cent of Singaporeans worry they will be a victim of online crime.

He spends over $1,300 on gift cards to meet 'sexy teen'

Seduced by unsolicited sexy pictures sent to him via the free messaging application WeChat, John (not his real name) sent over $1,300.

The 55-year-old never saw his money again.

Colleagues had introduced him to WeChat as a way of making new friends.

In late October, someone claiming to be a student in a local university started chatting with him.

John said: "She looked so innocent and decent (in the WeChat display picture), I never expected it to be a scam." After befriending him for eight days, the student told him she needed him to help buy iTunes gift cards for her studies.

A serial number on the back of the iTunes card will let a user download music, movies, games or apps, according to the card's value.

She also told him she would meet him at 10pm near his place, as long as he bought the card for her.

But after he bought the first card, which cost $150, her "big brother" started messaging John, telling him to pay an additional fee to meet her.

He told John to snap pictures of the serial number on the iTunes cards, so they did not have to meet physically.

Altogether, John bought nine cards, hoping he would finally meet her.

But at around 1.30am, he became suspicious because more than three hours had passed and he had not met the girl.

Hundreds of local men fell for sex scams and lost thousands

When John refused to continue buying more cards, the "big brother" started sending threatening messages and even pictures of his "past victims" to scare him.

When John still refused, the girl went back online and started sending sexy pictures to seduce him into buying even more cards.

Realising it was a scam, he made a police report at 3am.

John said: "I feel so stupid to have fallen into the trap.

"I've learnt my lesson and the public needs to know the WeChat scam may seem unusual, but (there are people) out to harm us."

Other victims have fallen prey to more conventional cheating scams.

In 2010, when she was 16, Regine started a blogshop.

She then found a page on social network Facebook that did preorders for shoes, contact lenses, polaroid cameras and more. Because she was in need of a supplier, she ordered more than 20 pairs of shoes with registered postage and paid over $200.

She said: "It seemed like a trusted page since it's from Singapore."

At first, she was told the stocks were delayed. Later, the seller allegedly went "missing" and even deactivated the Facebook page.

"I feel like an idiot, but at least now I'm more careful not to fall prey again," she said.

She was not the only victim.

On July 25, 2012, the police arrested two 16-year-old girls believed to have cheated at least 70 people of about $12,000 between May and June.

If convicted of cheating, they face up to 10 years' jail and a fine.

Types of online scams

1. NIGERIAN

Usually comes in the form of an e-mail informing a recipient he has 'won' an unexpected inheritance, which can be collected in return for a 'small payment' first. The scams can also include the planting of sophisticated software on computers that sucks out all personal information.

2. SMISHING

So-called "smishing", or SMS plus "phishing", is a variant that thrives on the rising popularity of smartphones. Scammers pose as banks or credit card companies to acquire personal details.

3. LOTTERY

Unexpected prize or lottery scams usually work by asking you to pay some sort of fee to claim your prize or winnings from a competition or lottery you never entered.

Scammers will often say these fees are for insurance costs, taxes, bank fees or courier charges.

The scammers make money by continually collecting these fees from you and stalling the payment of your winnings.

4. CREDIT-FOR-SEX

Usually takes place on messaging applications, promising to provide sexual services, but not delivering after payment.

5. E-COMMERCE

It relates to promises to provide a product or service that is not delivered after payment.